I'm a newbie as well but from what i got:
Max distance is different from max altitude!
Height limit is 500m. Basically If you're not in beginner mode the distance limit is given by the signal strenght: when you loose signal, the phantom comes back home or do whatever you programmed it to do.
With some apps like Litchi in theory you can programme waypoints and fly as far as the battery stays alive

As people have tried explaining to you - there is a maximum altitude (height) limit of 500m.

As for distance, there is NO limit. Make sure u are not in beginner mode, and then the only 'limit' on distance is your signal strength (and your battery power remaining - remember, you gotta leave enough battery power to get back home i.e. The further you are away from home point, the more battery you need to get back home safely!)

So, providing you have a good signal strength, there is NO distance limit.

The 500m limit you are talking about is the HEIGHT (altitude) limit that is built into the Phantom. This limit is not able to be increased.